Most of the top US brass were against use of the bomb and did not regard it as militarily necessary (See quotes below). Truman and Byrnes delayed the end of the war and cost American and Asian lives by deliberately refusing to clarify the surrender terms, by deliberately stalling Sino-Soviet talks, by deliberately postponing the Potsdam conference, and by deliberately ignoring the many Japanese peace feelers.
Quotes by US military leaders WWII.
"It is my opinion that the use of this barbarous weapon at Hiroshima and Nagasaki were of no material assistance in our war against Japan. The Japanese were already defeated and ready to surrender.....My own feeling was that in being the first to use it, we had adopted the ethical standard common to the barbarians of the Dark Ages. I was not taught to make war in that fashion, and wars cannot be won by destroying women and children."
Admiral William D. Leahy. 5-star admiral, president of the US Joint Chiefs of Staff and the combined American-British Chiefs of Staff, and chief of staff to the commander-in-chief of the army and navy from 1942 - 1945 (Roosevelt) and 1945 - 1949 (Truman).
"...I felt that it was an unnecessary loss of civilian life......We had them beaten. They hadn't enough food, they couldn't do anything."
Fleet Admiral Chester W. Nimitz, commander in chief of the Pacific Fleet, quoted by his widow.
"Nimitz considered the atomic bomb somehow indecent, certainly not a legitimate form of warfare."
E. B. Potter, naval historian.
"The first atomic bomb was an unnecessary experiment......It was a mistake ever to drop it......(the scientists) had this toy and they wanted to try it out, so they dropped it......It killed a lot of Japs, but the Japs had put out a lot of peace feelers through Russia long before."
Admiral William "Bull" Halsey, commander of the Third Fleet.
"Especially it is good to see the truth told about the last days of the war with Japan.....I was with the Fleet during that period; and every officer in the Fleet knew that Japan would eventually capitulate from...the tight blockade. "I, too, felt strongly that it was a mistake to drop the atom bombs, especially without warning."
Rear Admiral Richard Byrd.
(The atomic bomb) "was not necessary to bring the war to a successful conclusion.....it was clear to a number of people...that the war was very nearly over. The Japanese were nearly ready to capitulate.....it was a sin - to use a good word - (a word that) should be used more often - to kill non-combatants...."
Rear Admiral Lewis L. Strauss, special assistant to the Secretary of the Navy.
"The war would have been over in two weeks without the Russians entering and without the atomic bomb........the atomic bomb had nothing to do with the end of the war at all."
Major General Curtis E. LeMay, US Army Air Forces (at a press conference, September 1945).
"Russia's entry into the Japanese war was the decisive factor in speeding its end and would have been so even if no atomic bombs had been dropped..."
Major General Claire Chennault, founder of the Flying Tigers, and former US Army Air Forces commander in China.
"....from the Japanese standpoint the atomic bomb was really a way out. The Japanese position was hopeless even before the first atomic bomb fell..."
Henry H. "Hap" Arnold, Commanding General of the US Army Air Forces.
"Arnold's view was that it (dropping the atomic bomb) was unnecessary. He said that he knew that the Japanese wanted peace. There were political implications in the decision and Arnold did not feel it was the military's job to question it...........I knew nobody in the high echelons of the Army Air Force who had any question about having to invade Japan."
Lieutenant General Ira C. Eaker, Arnold's deputy.
"When the question comes up of whether we use the atomic bomb or not, my view is the the Air Force will not oppose the use of the bomb, and they will deliver it effectively in the Commander in Chief decide to use it. But it is not necessary to use it in order to conquer the Japanese without the necessity of a land invasion."
Arnold, quoted by Eaker.
"No! I think we had the Japs licked anyhow. I think they would have quit probably within a week or so of when they did quit."
General George C. Kenney, commander of Army Air Force units in the Southwest Pacific, when asked whether using the atomic bomb had been a wise decision.
"...Both felt Japan would surrender without use of the bomb, and neither knew why a second bomb was used."
W. Averall Harriman, in private notes after a dinner with General Carl "Tooey" Spaatz (commander in July 1945 of the Pacific-based US Army Strategic Air Forces, and Spaatz's one-time deputy commanding general in Europe, Frederick L. Anderson.
"I voiced to him (Secretary of War Stimpson) my grave misgivings, first on the basis of my belief that Japan was already defeated and that dropping the bomb was completely unnecessary, and secondly because I thought that our country should avoid shocking world opinion by the use of a weapon whose employment was, I thought, no longer mandatory as a measure to save American lives. It was my belief that Japan was at that very moment seeking some way to surrender with a minimum loss of 'face'........It wasn't necessary to hit them with that awful thing"
General Dwight D. Eisenhower.
"I told MacArthur of my memorandum of mid-May 1945 to Truman, that peace could be had with Japan by which our major objectives would be accomplished. MacArthur said that was correct and that we would have avoided all of the losses, the Atomic bomb, and the entry od Russia into Manchuria."
Herbert Hoover.
"MacArthur once spoke to me very eloquently about it....He thought it a tragedy that the Bomb was ever exploded. MacArthur believed that the same restrictions ought to apply to atomic weapons as to conventional weapons, that the military objective should always be to limit damage to noncombatants.... MacArthur, you see, was a soldier. He believed in using force only against military targets, and that is why the nuclear thing turned him off, which I think speaks well of him."
Richard M. Nixon.
"...he saw no military justification for the dropping of the bomb. The war might have ended weeks earlier, he said, if the United States had agreed, as it did later anyway, to the retention of the institution of the emperor."
Norman Cousins, from an interview with MacArthur.